Electronic Throttle Control Module: Testing and Inspection
Throttle Valve Control Module Checking
• Use only gold-plated terminals when servicing terminals in harness connector of this system.
Special tools, testers and auxiliary items required
• Multimeter.
• Wiring diagram.
Test requirements
• The Engine Control Module (ECM) (J623) fuses OK.
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• Vehicles with automatic transmission, shift selector lever into position "P" or "N".
• A/C switched off.
• Ground connections between engine/transmission/chassis OK.
• Throttle valve must not be damaged or dirty.
• Coolant Temperature at least 80° C.
Function
Throttle valve operation occurs by an electric motor Throttle Drive Electronic Power Control (EPC) (G186) in Throttle Valve Control Module (J338). It is operated by Engine Control Module (ECM) (J623) according to specifications of Throttle Position (TP) Sensor (G79)/Accelerator Pedal Position Sensor 2 (G185).
Components of Throttle Valve Control Module (J338):
• Throttle Drive Electronic Power Control (EPC) (G186)
• Throttle Drive Angle Sensor 1 (for Electronic Power Control (EPC) (G187)
• Throttle Drive Angle Sensor 2 (for Electronic Power Control (EPC) (G188)
Test procedure
- Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] Preliminary Check.
Start diagnosis
- Connect the scan tool.
- Switch ignition On.
- Using the scan tool, check the throttle valve position (absolute) at idle stop:
- Slowly depress the accelerator pedal to Wide Open Throttle (WOT) stop while observing the percentage display. The percentage display must increase uniformly.
- Using the scan tool, check the throttle valve position (absolute) at Wide Open Throttle (WOT) stop:
- Switch ignition Off.
If the specified values are Not obtained:
- Remove the Throttle Valve Control Module (J338) far enough so that the electrical connector terminals are reached.
- Disconnect the Throttle Valve Control Module (J338) electrical harness connector.
Checking resistance
- Using a multimeter, check the Throttle Drive Electronic Power Control (EPC) (G186) at the Throttle Valve Control Module (J338) terminals 3 to 5 for resistance.
Specified value: 1.0 to 5.0 ohms (at 20° C)
If the specification was Not obtained:
- Replace the Throttle Valve Control Module (J338).
If the specification was obtained:
Checking voltage supply
- Switch the ignition On.
- Using a multimeter, check the Throttle Drive Electronic Power Control (EPC) (G186) at the Throttle Valve Control Module (J338) electrical harness connector terminals 2 to 6 for voltage.
Specified value: at least 4.5 V
- Switch the ignition Off.
If the specified value was obtained:
- Replace the Throttle Valve Control Module (J338).
If the specified value was Not obtained:
Checking wiring
If the manufacturers test box is being used. Perform the following step.
- Install the test box.
If the manufacturers test box is not being used. Perform the following step.
- Remove the Engine Control Module (ECM) (J623). Refer to the Repair Information.
- Using a multimeter, check the Throttle Drive Electronic Power Control (EPC) (G186) at Throttle Valve Control Module (J338) electrical harness connector terminals to the Engine Control Module (ECM) (J623) electrical harness connector T121 terminals for resistance.
Specified value: 1.5 ohms max.
If the specification is Not obtained:
- Check the wiring for an open circuit, high resistance, a short circuit to each other, Battery (+) or Ground.
- If necessary, repair the faulty wiring connection.
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
If no malfunction is found in the wiring and the voltage supply was not OK:
- Erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.
- Perform a road test to verify repair.
If the DTC does not return:
Generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.
If the DTC returns, no malfunction is found in the wiring and the voltage supply was OK:
- Replace the Engine Control Module (ECM) (J623). Refer to the Repair Information.
- Assembly is performed in the reverse of the removal.
Final procedures
After repair work, the following work steps must be performed in the following sequence:
1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Modes 01 - 09.
2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.
3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.